mobmonitor: Mob* Monitor Checkfile Execution

This CL implements the execution of the Check and Diagnose
functions that are defined in health check classes.

This bug assumes that Check functions are fast. Handling
long health checks will be the focus of crbug.com/501959.

It is assumed that executing Diagnose is fast as it simply
maps a failure code to a description and set of repair actions.

BUG=chromium:490798,chromium:490801
TEST=Unittests and tested on local machine.

Change-Id: If82e8663e14ef3e3872b7ff8b677a56ffb5e22fa
Reviewed-on: https://chromium-review.googlesource.com/280387
Tested-by: Matthew Sartori <msartori@chromium.org>
Reviewed-by: Simran Basi <sbasi@chromium.org>
Commit-Queue: Matthew Sartori <msartori@chromium.org>
3 files changed